ausblenden:
Schlagwörter:
-
Zusammenfassung:
We describe the design and development of
the
fi
rst catalytic asymmetric vinylogous Prins cyclization.
This reaction constitutes an e
ffi
cient approach for highly
diastereo- and enantioselective synthesis of tetrahydrofur-
ans (THFs) and is catalyzed by a con
fi
ned chiral
imidodiphosphoric acid (IDP). Aromatic and heteroar-
omatic aldehydes react with various 3,5-dien-1-ols to a
ff
ord
2,3-disubstituted THFs in excellent selectivity (d.r. > 20:1,
e.r. up to 99:1). Aliphatic aldehydes react with similarly
excellent results when a highly acidic imidodiphosphor-
imidate (IDPi) catalyst is used. With a racemic dienyl
alcohol, the reaction proceeds via a kinetic resolution.
DFT calculations suggest an explanation for unusually high
stereoselectivity.
